1. Field of the Invention
The present invention relates to an ultrasonic Doppler diagnosis device for measuring the velocity of a kinetic reflector such as a blood flow within a living body.
2. Description of the Related Art
An ultrasonic Doppler diagnosis device has been known for measuring a blood flow velocity within a living body, for example. When such an ultrasonic Doppler diagnosis device displays a two-dimensional Doppler view to represent spatial distribution of a velocity of a kinetic reflector such as a blood flow, the device passes a Doppler shift signal through an autocorrelator, obtains an average frequency from complex output data from the autocorrelator by an operation, and spatially interpolates the calculated average frequency for display.
However, there is a problem in that for frequency aliasing caused around a Nyquist frequency decided depending on a sampling frequency of a Doppler shift signal, a maximum value of a positive velocity (bright red) and a maximum value of a negative velocity (bright blue) are averaged, so that an average frequency is interpolated in incorrect data (a dark color with a velocity being approximately 0) where bright blue or bright red should be interpolated in the correct way.
In order to solve the problem as above, for example, Japanese Patent Laid-Open No. 2678124 proposes an ultrasonic Doppler diagnosis device to solve disadvantages of data interpolation due to frequency aliasing by obtaining complex interpolation data of each pixel between scanning lines and by operating velocity data from an argument of the complex interpolation data.